Transcript Catholic University College of Ghana Fiapre

Catholic University College of Ghana
Fiapre-Sunyani
System Software
Input Devices
INFORMATION TECHNOLOGY I
Audrey Asante, Faculty of ICST
SYSTEM SOFTWARE
• It enables the application software to interact with
the computer and helps the computer manage its
internal and external resources.
• There are four basic types of system software
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Operating systems
Utility programs
Language translators
Device drivers
Components of System Software
• Operating systems are programs that operate your
microcomputer. They coordinate computer resources, provide
an interface between users and the computer, and run
applications.
• Utilities, also known as service programs, perform specific
tasks related to managing computer resources or files. They
include programs to help users identify hardware problems,
locate lost files, and back up data.
• Device drivers are specialized programs designed to allow
particular input or output devices to communicate with the
rest of the computer system.
• Language translators convert the programming instructions
written by programmers into a language that computers
understand and process.
Functions of the Operating System
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Booting
Managing storage media
User interface
Managing computer resources
Managing files
Managing tasks
TYPES OF OS
• Real-time Operating System: It is a
multitasking operating system that aims at
executing real-time applications. Real-time
operating systems often use specialized
scheduling algorithms so that they can
achieve a deterministic nature of behavior.
The main object of real-time operating
systems is their quick and predictable
response to events.
Real Time OS
• They either have an event-driven or a timesharing design. An event-driven system
switches between tasks based on their
priorities while time-sharing operating
systems switch tasks based on clock
interrupts.
TYPES OF OS
• Multi-user and Single-user Operating
Systems: The operating systems of this type
allow a multiple users to access a computer
system concurrently. Time-sharing system can
be classified as multi-user systems as they
enable a multiple user access to a computer
through the sharing of time. Single-user
operating systems, as opposed to a multi-user
operating system, are usable by a single user
at a time.
Multi-user and Single-user
Operating Systems
• Being able to have multiple accounts on a
Windows operating system does not make it a
multi-user system. Rather, only the network
administrator is the real user. But for a Unixlike operating system, it is possible for two
users to login at a time and this capability of
the OS makes it a multi-user operating system.
TYPES OF OS
• Multi-tasking and Single-tasking Operating
Systems: When a single program is allowed to
run at a time, the system is grouped under a
single-tasking system, while in case the
operating system allows the execution of
multiple tasks at one time, it is classified as a
multi-tasking operating system. Multi-tasking
can be of two types namely, pre-emptive or
co-operative.
Multi-tasking and Single-tasking
Operating Systems
• In pre-emptive multitasking, the operating
system slices the CPU time and dedicates one
slot to each of the programs. Unix-like
operating systems such as Solaris and Linux
support pre-emptive multitasking.
Cooperative multitasking is achieved by
relying on each process to give time to the
other processes in a defined manner. MS
Windows prior to Windows 95 used to
support cooperative multitasking.
TYPES OF OS
• Distributed Operating System: An operating
system that manages a group of independent
computers and makes them appear to be a
single computer is known as a distributed
operating system. The development of
networked computers that could be linked
and communicate with each other, gave rise
to distributed computing.
Distributed Operating System
• Distributed computations are carried out on
more than one machine. When computers in a
group work in cooperation, they make a
distributed system.
TYPES OF OS
• Embedded System: The operating systems
designed for being used in embedded
computer systems are known as embedded
operating systems. They are designed to
operate on small machines like PDAs with less
autonomy. They are able to operate with a
limited number of resources. They are very
compact and extremely efficient by design.
Windows CE, FreeBSD and Minix 3 are some
examples of embedded operating systems.
TYPES OF OS
• The operating systems thus contribute to the
simplification of the human interaction with
the computer hardware. They are responsible
for linking application programs with the
hardware, thus achieving an easy user access
to the computers.
UTILITIES
• There are hundreds of different utility
programs. The five most essential utilities are;
– Troubleshooting programs that recognize and
correct problems, ideally before they become
serious problems.
– Antivirus programs
– Uninstall programs
– Back up programs
– File compression programs
UTILITY SUITES
• Like application software suites, utility suites combine several
programs into one package. Example is Norton Utilities
• Norton Utilities is a collection of 17 separate troubleshooting
utilities. These programs can be used to find and fix problems,
improve system performance, prevent problems from
occurring, and troubleshoot a variety of other problems.
• Norton Antivirus
• Norton cleansweep (guards for one to safely remove a
program and files that are no longer needed. They can also
protect existing files from damaging when new programs are
installed. They make backups as well as clean hard disk.
UTILITY SUITES
• Norton crashguard (intervenes to provide
options for recovering current work)
• Norton web services ( notifies of available
software updates to be automatically installed
from the internet)
Input Devices
• Keyboard
• Mouse
Keyboard Layout
• QWERTY: A standard computer keyboard is called a QWERTY
keyboard because of the layout of its typing area. This keyboard is named
after the first six leftmost letters on the top alphabetic line of the
keyboard. A QWERTY keyboard might limit your typing speed.
• DVORAK: A keyboard with an alternative layout was designed to
improve typing speed. Called the Dvorak keyboard, this type of keyboard
places the most frequently typed letters in the middle of the typing area.
Types of Keyboard
• Wireless keyboards: The most obvious difference between a wireless
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keyboard and a normal one is that the former uses infrared beams to transfer data
to the computer as opposed to the latter, which uses a wire. As you type, a beam
of data is sent from your keyboard to a receiver on the computer. The major
advantage of this is that it eliminates one wire from the entangled web of wires
from behind your desk. Many people also prefer to have a wireless mouse along
with a wireless keyboard.
It may not be possible for a corded keyboard to be kept in a particular place that is
most comfortable to you. This is possible with a cordless keyboard, provided that it
is placed in a position where the infrared beam is easily reachable by the
computer. This distance can be different for different computers, so it makes sense
to check the specifications before buying a wireless keyboard. This feature can be
a problem for the user if an object or person happens to block the path of the
infrared beam or the angle of the keyboard is not right.
A wireless keyboard can be a valuable component is you are certain that the space
between your keyboard and computer will remain free of physical obstructions. It
will provide freedom and flexibility.
Ergonomic keyboard
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The ergonomic keyboard has been designed to relieve some of the stress caused
by repetitive typing and make for more comfortable typing. Prolonged usage of the
keyboard can cause carpal tunnel syndrome or repetitive stress injury, which can
be very painful. The specially designed, contoured ergonomic keyboards are
helpful in such cases and even recommended by doctors.
There is also a view that the traditional QWERTY layout is more stressful on the
fingers and arms. Hence, the unconventional Dvorak keyboard layout has been
designed for those who subscribe to this theory.
While there are no design specifications for ergonomic keyboards, they generally
have a contoured design for greater typing comfort, as opposed to the standard
flat keyboard.
Illuminated keyboards
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Much like mobile phone keyboards, these keyboards are backlit so that the keys
are more visible even in poorly lit conditions.
Often, when working at night, you may like to work only with the light of the
monitor to prevent the glare of another light. An illuminated keyboard would be
just the thing for you in such a situation. It is also great for multimedia
presentations in boardrooms with dim lighting.
Connection Types
• Wireless keyboard
• PS/2 keyboard
• USB keyboard
Explanation of the Keys on a Windows QWERTY
Keyboard
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Q W E R T Y "The name "QWERTY" for our computer keyboard comes
from the first six letters in the top alphabet row (the one just below the
numbers). It is also referred to as the "Universal" keyboard. It was the
work of inventor C. L. Sholes, who put together the prototypes of the first
commercial typewriter in a Milwaukee machine shop back in the 1860's.”
• Esc Equivalent to clicking the Cancel button. In PowerPoint the Esc key will
stop a running slide show. On a web page with animations, the Esc key will
stop the animations. On a web page that is loading, the Esc key will stop
the page from loading. The keyboard combination Ctrl + Esc will open the
Start Menu.
• F1 While working in an application, depressing this key will bring up the
applications help menu. If there is no open application F1 will open
Windows Help.
• F2 Choose this key to rename a selected item or object.
• F3 Depressing this key will display the Find: All Files dialog box.
• F4 Selects the Go To A Different Folder box and moves down the entries in
the box (if the toolbar is active in Windows Explorer)
• F5 Refreshes the current window. In Internet Explorer, F5 will Refresh the
web page.
• F6 Moves among panes in Windows Explorer.
• F10 Activates menu bar options. Use right and left arrows to select menus
and down arrows to display pull down menus.
• F11 In Internet Explorer this key will allow you to toggle between full
screen viewing mode and normal viewing mode.
• Print Screen/SysRq Usually located at the upper right hand corner of your
keyboard next to the Scroll Lock and Pause/Break keys. Often abbreviated
PrtScr, the Print Screen key is a useful key supported on most PCs. In DOS,
pressing the Print Screen key causes the computer to send whatever
images and text are currently on the display screen to the printer. Some
graphics programs and Windows, use the Print Screen key to obtain
Screen Captures.
• Tab This key can be used to move forward through options in a dialog box.
Ctrl + Shift + Tab can be used to move backward through the options. Ctrl
+ Tab allows movement from one open window to the next in an
application with more than one open window. Alt + Tab displays a list of
open application windows. Keeping Alt depressed and selecting Tab cycles
through the list. Releasing selects the highlighted application window.
• Caps Lock Locks the keyboard in "Capitals" mode (only applies to Alpha
keys). The Caps Lock key should be used with caution. Using ALL CAPS is a
usability no-no as many have difficulty scanning text that is ALL CAPS. Also,
when sending email in all caps, this could be misconstrued as shouting at
someone.
• Shift The obvious use of this key is to allow selection of capital letters
when depressing the alphabet characters, or selecting the characters
above other non-alpha keys. Depressing the Shift key while inserting a CDROM will bypass auto play. Shift + Delete to permanently delete a selected
item, bypasses the Recycle Bin.
• Control Key: Ctrl Depressing the Ctrl key while clicking allows multiple
selections. Holding the Ctrl key down and pressing other key combinations
will initiate quite a few actions. Some of the more common ones are listed
below.
• Ctrl + A Select All items
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Ctrl + B Add or remove Bold formatting
Ctrl + C Copy, places the selected/highlighted copy on the clipboard.
Ctrl + C + C Opens the clipboard.
Ctrl + F Opens the Find what: dialog box. Great for finding references on a
web page while using your favorite web browser.
• Ctrl + H Replace, brings up the Find and Replace dialog box. Great for
global find and replace routines while working in normal and html views in
your favorite WYSIWYG editors like FrontPage. You can also use this to find
and replace content within your Word Documents, Excel Spreadsheets,
etc...
• Ctrl + I Add or remove Italic formatting.
• Ctrl + N Window, In Internet Explorer, opens a New Window. In Outlook,
opens a New Mail Message. In most publishing programs like Word, opens
a New Document.
• Ctrl + O Open, brings up a browse dialog and allows you to select a file to
open.
• Ctrl + P Print
• Ctrl + S Save
• Ctrl + U Add or remove Underline formatting.
• Ctrl + V Paste, inserts the copy on the clipboard into the area where your
flashing cursoris positioned or the area you have selected/highlighted.
• Ctrl + W Close, will close the document currently open.
• Ctrl + X Cut, removes the selected/highlighted copy and places it on the
clipboard.
• Ctrl + Y Redo last command. Many software programs offer multiple
Redo's by pressing Ctrl + Y + Y + Y...
• Ctrl + Z Undo last command. Many software programs offer multiple
Undo's by pressing Ctrl + Z + Z + Z...
• Ctrl + Esc Open the Start menu (or use the Windows Key if you have one).
• Ctrl + = Spell checker (pre WinXP).
• Ctrl While dragging a file to copy the file.
• Ctrl + Shift While dragging a file to create a shortcut.
• Ctrl + Tab Allows movement (toggle) from one open window to the next in
an application with more than one open window.
• Ctrl + F4 Close a window in an application without closing the application.
• Ctrl + F5 In Internet Explorer, Ctrl + F5 will Refresh the web page bypassing
cache (all images and external file references will be reloaded).
• Windows Key
• Windows Key On either side of the spacebar, outside the Alt key, is a key
with the Windows logo. Holding the Windows key down and pressing
another key will initiate quite a few actions.
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Some of the more common are listed in the table below:
Displays the Start Menu.
+ D Minimizes all windows and shows the Desktop.
+ D Opens all windows and takes you right back to where you were.
+ E Opens a new Explorer Window. Probably one of the hottest Windows
keyboard shortcuts. This one gets a lot of hoorahs!
+ F Displays the Find all files dialog box.
+ L Lock your Windows XP computer. Logoff in Windows Pre-XP.
+ M Minimizes all open windows.
+ Shift + M Restores all previously open windows to how they were before
you Minimized them.
+ R Displays the Run command.
+ F1 Displays the Windows Help menu.
+ Pause/Break Displays the Systems Properties dialog box.
• + Tab Cycle through the buttons on the Task Bar.
• Alt: Alt Located on either side of the space bar. Holding the Alt key down
and pressing another key will initiate various actions. Some of the more
common ones are listed below:
• Alt + F4 Closes the current active window. If there is no active window this
opens the Shut Down dialog box.
• Alt + underlined letter in menu To carry out the corresponding command
on the menu.
• Alt + left/right arrows In a browser moves forward or back through the
pages visited in a window.
• Alt + Space Bar Displays the current window's system menu. This is the
same as left clicking on the application icon at the top left of the window.
• Alt + Enter Displays a selected items properties. This can also be done with
Alt + double-click.
• Alt + PrtScn Captures the top window of the active application.
• Alt + Space Bar Displays the main window's system menu. This is the same
as clicking on the application icon at the left end of the title bar.
• Alt + Space Bar + C After the system menu is displayed (see above), this
combination will close a window. This works the same way as Alt + F4 but
requires less stretch.
• Alt + - (hyphen) Displays the current window's system menu. This is the
same as left clicking on the application icon at the top left of the window.
• Alt + Tab Displays a list of open application windows. Keeping Alt
depressed and selecting Tab cycles through the list. Releasing selects the
highlighted application window.
• Alt Ctrl The Application key has an image of a mouse pointer on a menu
(between the Alt and Ctrl keys () to the right of your Space Bar).
Depressing this key will display the selected item's shortcut window. This
is the menu that is displayed by right-clicking.
• Space Bar Insert a space between words. It is suggested that you utilize
Tabs (or other formatting commands) to put distance between elements.
Using the space bar to insert visual space works but would not be
considered a best practice in page design. Double spaces between
sentences are no longer required. This is a carryover from the days of fixed
width fonts on a typewriter such as Courier, Orator, Prestige Elite, etc.
Pressing the Space Bar while viewing a web page in Internet Explorer will
scroll the page downwards. Shift + Space Bar will scroll the page upwards.
• Enter Creates a new Paragraph <p> () or what is referred to as a Hard
Return. In any dialog box a selected button or command can be selected
by depressing this key. Selected buttons can be recognized by their darker
(dotted) borders, or what is referred to as Focus.
• Shift + Enter Creates a new Line Break <br> () or what is referred to as a
Soft Return.
• Shift + Arrow Shift + Arrow Up, Down, Left or Right. Position your cursorat
the beginning of the area you wish to highlight for copying. Now use the
up, down, left or right arrow keys to select areas of content to be
highlighted, copied, pasted, etc.
• Backspace While working with text, use this key to delete characters to
the left of the insertion point.
• Home Depress and hold the Ctrl key as you select Home to go to the first
line of a document.
• Page Up In a browser window use the Page Up key to move up one full
screen on a web page.
• Delete While working with text, use this key to delete characters to the
right of the insertion point. This key can also be used to delete selected
files. If you use the keyboard combination Shift + Delete the item is
permanently deleted, bypassing the Recycle Bin.
• End Depress and hold the Ctrl key as you select End to go to the last line of
a document.
• Page Down In a browser window use the Page Down key to move down
one full screen on a web page
• Up Arrow Navigate in a document to the line above. Hold the Ctrl key
down as you press this key to move to the beginning of the second line
above.
• Right Arrow Navigate in a document one character to the right. Hold the
Ctrl key down as you press this key to move one word to the right.
• Down Arrow Navigate in a document to the line below. Hold the Ctrl key
down as you press this key to move to the beginning of the second line
below.
• Left Arrow Navigate in a document one character to the left. Hold the Ctrl
key down as you press this key to move one word to the left.
• Keypad Keys
• Num Lock If you want to use the numeric keypad on the right end of the
keyboard to display numbers, the Num Lock key must be selected (usually
a light above the Num Lock will indicate that it is on). If you want to use
the keypad to navigate within a document, turn off Num Lock by pressing
the key (the light will go off).
• * (Asterisk) In Windows Explorer this expands everything under the
current selection. Caution: do not try this with the C Drive icon selected.
• - (Minus Sign) In Windows Explorer this collapses the current selection.
• + (Plus Sign) In Windows Explorer this expands the current selection.
FEATURES OF THE KEYBOARD
• Special purpose keys: are used to enter, delete, and
edit data and to execute commands.
• Function keys: are used to execute commands
specific to the software being used
• Macros: are also called keyboard shortcuts. It is a
single keystroke or command used to automatically
issue a longer, predetermined series of keystrokes or
commands.
Mouse
• The mouse is a pointing device
• It allows for fine control of a Graphical User
Interface.
• The mouse parts
– Left mouse button
– Right button
– Scroll wheel-for scrolling. This is an additional
feature that has been added.
Mouse
• Types of mouse
– Mechanical Mouse device: This is a type of computer mouse that has
a rubber or metal ball on its underside and it can roll in every direction. There
are sensors within the mouse, which are mechanical, detect the direction in
which the ball is moving and moves the pointer on the screen in the same
direction. A mouse pad should be used under the mouse to run on.
– Optomechanical mouse devices:
This is the same as the
mechanical mouse except that it uses optical sensors to the motion of the
ball. Your should use a mouse pad under the mouse to run on.
– Optical mouse device: This type uses a laser for detecting the mouse's
movement. You don't need a
mouse pad but you can use one made for optical mice. Optical mice do not
have any mechanical moving parts. The optical mouse responds more quickly
and precisely than the mechanical and optomechanical mice and now that
they have been around awhile the price is pretty comparable.
Here is how a computer mouse hooks up to the computer
• Serial mouse: these ones connect directly to an RS-232C serial port or
a PS/2port. This is the simplest type of connection. it requires a free serial
port on your PC.
• PS/2 mouse: connects to a PS/2 port.
USB Mouse - This type of mouse has a USB connector and requires a
free USB port.
• Cordless mouse: These are not physically connected to the
computer. They rely on infrared or radio waves to communicate with the
computer. Cordless are more expensive than both the serial and bus
mouse. The nice thing is that there is no cord to constrain or get in your
way. this type of mouse utilises batteries for its power supply.
Optical Mouse - An optical mouse utilises optical electronics to track
the mouse's position and movement, they are preferred over standard
mechanical mice as they tend to be more reliable and require less
maintenance.
Mouse
• Applications or directions of the mouse
– Single click
– Double click
– Triple click
– Drag and drop
– Roll over
– Selecting
– Pointing